Short take off and landing aircraft

ABSTRACT

An aircraft has a pilot compartment and a power source, apparatus adapted to control attitude and direction, apparatus adapted to vary power of the power source, sensors sensing at least altitude, airspeed, power level, and aircraft attitude, a CPU coupled to a data repository, to the sensors and to actuators adapted to change the flight attitude and direction and to vary power, and safe flight envelope data and conditions stored in the data repository defining flight conditions at boundaries of safe and unsafe operation. The CPU monitors the sensors while the aircraft is in operation, determines if flight status is outside the safe flight envelope, and if so, drives appropriate actuators to manipulate the apparats adapted to control flight attitude and direction and/or the apparatus adapted to vary power of the power source in a programmed manner until the flight status is within the safe flight envelope.

CROSS REFERENCE TO RELATED APPLICATIONS

The instant application is a Continuation-in-Part of U.S. applicationSer. No. 17/463,471 Short Take Off And Landing Aircraft, filed Aug. 3,2021, which is a Continuation-in-Part of U.S. application Ser. No.16/941,420, having the title, Short Take Off And Land Aircraft, filedJul. 28, 2020, which is herein incorporated at least by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention is in the technology area of fixed wing aircraftand pertains more particularly to automated maintenance of a flightenvelope in operation.

2. Description of Related Art

The technology of Short Takeoff and Landing (STOL) for fixed wingaircraft is well known in the art, and there are numerous examples ingeneral literature and in patent literature. The length of runway forsuch aircraft to takeoff and land varies among different designs andmodels of aircraft, and the technology enabling STOL also varies.

STOL is typically defined as an ability of an aircraft to clear a50-foot (15 meters) obstacle within 1,500 feet (450 meters) ofcommencing takeoff or in landing, to stop within 1,500 feet (450 meters)after passing over a 50-foot (15 meters) obstacle.

There are various reasons for providing aircraft capable of STOL, suchas reduced cost for runway building and maintenance. In militaryapplications STOL aircraft can use very short runways that arerelatively easy to build and maintain in forward positions and in combatsituations. Helicopters have long been available to land and takeofffrom reduced areas, such as helipads on rooftops, but helicopters havean offsetting disadvantage of being slower in horizontal flight andexpensive to operate.

At the time of filing this patent application the planet is in themiddle of a pandemic called the Covid-19 virus pandemic. People are atrisk in third-world regions where airports with long runways are few, soevacuating effected persons to hospital, for example, is a challenge,and great efforts are also underway to develop vaccines and othereffective treatments for Covid-19. When a vaccine is available andmanufactured in quantity there will be a pressing need for deliveringquantities of vaccine to remote areas to inoculate people. The presentstate of STOL fixed wing aircraft may be an advantage in deliveringvaccine and medications in the pandemic, but what is clearly needed is aSTOL fixed wing aircraft that can takeoff and land in much shorterdistances that can aircraft in the art at the time of filing this patentapplication.

It is also well established that fixed wing aircraft operate withing asafe flight envelope, comprising fixed and threshold values forperformance characteristics, that vary for every aircraft. What isclearly needed in this instance is a computerized system that monitorsperformance and status of the aircraft in real time, and automaticallyoperates drive and flight systems to maintain the flight envelope.

BRIEF SUMMARY OF THE INVENTION

An aircraft is provided having a pilot compartment and a power source.The aircraft comprises an apparatus adapted to control flight attitudeand direction, an apparatus adapted to vary power of the power source,sensors sensing at least altitude, airspeed, power level, and aircraftattitude, a CPU coupled to a data repository, to the sensors and toactuators adapted to change the flight attitude and direction and tovary power at the power source and safe flight envelope data andconditions stored in the data repository defining flight conditions atboundaries of safe and unsafe operation.

In this embodiment, the CPU monitors the sensors while the aircraft isin operation, determines if flight status is outside the safe flightenvelope, and if so, drives appropriate actuators to manipulate theapparatus adapted to control flight attitude and direction and/or theapparatus adapted to vary power of the power source in a programmedmanner until the flight status is within the safe flight envelope.

The aircraft, in this embodiment is a Vertical Take Off and Landing(VTOL) aircraft. Alternatively, the aircraft is a fixed wing aircraft,and the apparatus adapted to control flight attitude and directioncomprises ailerons, flaps, and a rudder. In this embodiment, theaircraft further comprises distributed electrically driven, individuallycontrollable propellers proximate one or more of ailerons, flaps orrudders, the motors powered by one or more on-board batteries. Inanother embodiment, the aircraft is a Short Takeoff and Landing (STOL)aircraft having a fuselage with a long axis and a primary engineproviding controllable primary forward thrust to propel the aircraft,further comprising a first aileron implemented proximate an end of afirst fixed wing extending from the fuselage, a second aileronimplemented proximate an end of a second fixed wing, opposite the firstfixed wing, a first slot having a length and a width through the firstfixed wing proximate the first aileron, the slot length substantiallyorthogonal to the axis of the fuselage, a second slot having a lengthand a width through the second fixed wing proximate the second aileron,the slot length substantially orthogonal to the axis of the fuselage, afirst reversible electric motor implemented in the first fixed wingdriving a first two-blade propeller in the first slot, a secondreversible electric motor implemented in the second fixed wing driving asecond two-blade propeller in the second slot, and a control mechanismaccessible to a user in a cockpit of the aircraft, the control mechanismenabling the user to drive the first and second electric motors in asame rotary direction, to reverse the rotary direction, and to drive thefirst and second electric motors at a same rpm in either rotarydirection. Additionally, slipper pods may be slung under the wings, thewings and the slipper pods housing batteries interconnected and coupledto the electric motors. The slipper pods may be adapted to be jettisonedon command.

The aircraft may include a plurality of slots in linear arrangementalong an edge of each aileron, each slot enclosing a two-blade propellerdriven by a reversible electric motor, wherein all of the propellers aredriven in concert. The aircraft may also include bays implemented in thewings, the bays housing batteries interconnected and coupled to theelectric motors. In this embodiment, the two-blade propeller in eachslot is adapted to be constrained wholly within the slot when not beingdriven by the associated electric motor.

A method is provided of maintaining operation of an aircraft having apilot compartment and a power source within a safe flight envelope,comprising the steps of 1) monitoring sensors sensing at least altitude,airspeed, power level, and aircraft attitude by a CPU coupled to a datarepository, to the sensors and to actuators adapted to control apparatusadapted to control flight attitude and direction to change the flightattitude and direction and to vary power at the power source; 2)determining whether flight status is outside a safe flight envelope bycomparison of real time sensed values to stored safe flight envelopedata and conditions in the data repository defining flight conditions atboundaries of safe and unsafe operation; and if so, driving appropriateactuators to manipulate the apparats adapted to control flight attitudeand direction and/or the apparatus adapted to vary power of the powersource in a programmed manner until the flight status is within the safeflight envelope.

In one embodiment the method includes a Vertical Take Off and Landing(VTOL) aircraft or a fixed wing aircraft having ailerons, flaps, and arudder. In this embodiment, the aircraft further comprises distributedelectrically driven, individually controllable propellers proximate oneor more of ailerons, flaps or rudders, the motors powered by one or moreon-board batteries.

One embodiment provides the method including a Short Takeoff and Landing(STOL) aircraft having a fuselage with a long axis and a primary engineproviding controllable primary forward thrust to propel the aircraft,further comprising a first aileron implemented proximate an end of afirst fixed wing extending from the fuselage, a second aileronimplemented proximate an end of a second fixed wing, opposite the firstfixed wing, a first slot having a length and a width through the firstfixed wing proximate the first aileron, the slot length substantiallyorthogonal to the axis of the fuselage, a second slot having a lengthand a width through the second fixed wing proximate the second aileron,the slot length substantially orthogonal to the axis of the fuselage, afirst reversible electric motor implemented in the first fixed wingdriving a first two-blade propeller in the first slot, a secondreversible electric motor implemented in the second fixed wing driving asecond two-blade propeller in the second slot, and a control mechanismaccessible to a user in a cockpit of the aircraft, the control mechanismenabling the user to drive the first and second electric motors in asame rotary direction, to reverse the rotary direction, and to drive thefirst and second electric motors at a same rpm in either rotarydirection.

The STOL aircraft may further comprise a plurality of slots in lineararrangement along an edge of each aileron, each slot enclosing atwo-blade propeller driven by a reversible electric motor, wherein allof the propellers are driven in concert. Additionally, the STOL aircraftmay further comprise bays implemented in the wings, the bays housingbatteries interconnected and coupled to the electric motors. In thisembodiment, the two-blade propeller in each slot is adapted to beconstrained wholly within the slot when not being driven by theassociated electric motor. Slipper pods may be added to the STOLaircraft slung under the wings, the wings and the slipper pods housingbatteries interconnected and coupled to the electric motors.Additionally, the slipper pods may be adapted to be jettisoned oncommand.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective illustration of a STOL fixed-wing aircraft in anembodiment of the present invention.

FIG. 2 is a perspective view of an aileron apparatus of the aircraft ofFIG. 1 in an embodiment of the invention.

FIG. 3 is a perspective view of a flap system shown extended from a wingof the aircraft of FIG. 1 in an embodiment of the invention.

FIG. 4A is a perspective view of a flap system in an alternativeembodiment of the invention.

FIG. 4B is a perspective view of propeller 402, extended.

FIG. 4C is a perspective view of propeller 402, folded.

FIG. 5 illustrates a control system in the aircraft of FIG. 1 in anembodiment of the invention.

FIG. 6 is a flow diagram representing a takeoff process in oneembodiment of the invention.

FIG. 7 is a flow diagram illustrating a landing process in an embodimentof the invention.

FIG. 8A illustrates a STOL fixed-wing aircraft in an alternativeembodiment of the invention.

FIG. 8B illustrates an enhanced aileron on a wing of the aircraft ofFIG. 8A.

FIG. 8C illustrates a tail section of the aircraft of FIG. 8A.

FIG. 9 illustrates a slipper pod for carrying batteries.

FIG. 10 illustrates a control lever for controlling power and directionto electric motors.

FIG. 11 illustrates an outboard propeller in another aspect of theinvention.

FIG. 12 illustrates an automated control system in an embodiment of theinvention.

FIG. 13 is a flow diagram illustrating operation of the control systemof FIG. 12 .

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a perspective illustration of a STOL fixed-wing aircraft 101in an embodiment of the present invention. In this example the aircraftis a fixed wing aircraft with a single engine 105 driving a propeller110, located at the front of the aircraft. Aircraft 101 has a fuselage103 a tail section 104 including a rudder, two fixed wings 102 a and 102b landing gear 106 including a nose wheel 107, aileron apparatus 108 aand 108 b, and flap apparatus 109 a and 109 b. Propeller 110 in someembodiments may be reversible to provide braking on landing, and may beblades adjustable for thrust, as is known in the art.

Aileron apparatus 108 a and b are implemented near the outboard ends ofwings 102 a and 102 b. The use of the ailerons is well-known in the artfor generating a rolling motion for the aircraft, which may precipitatea banking turn. Aileron control is critical in takeoff and landing,particularly in landing the aircraft. Ailerons usually work inopposition: as the right aileron is deflected upward, the left isdeflected downward, and vice versa. In embodiments of the inventionaileron apparatus 108 a and 108 b comprise additional elements enhancingoperation of the conventional aileron functions. These elements andoperation are described in enabling detail below.

Flap apparatus 109 a and 109 b implemented in wings 102 a and 102 b arewell-known as apparatus for increasing lift. Flaps extension isparticularly important in takeoff and landing as well and is critical inoperation of an aircraft intended for short takeoff and landing (STOL).Both the aileron apparatus and the flap apparatus are enhanced in aunique way in some embodiments of the present invention, and detail ofenhancements is provided below in enabling fashion.

FIG. 2 is a perspective view of aileron apparatus 108 b of aircraft 101in an embodiment of the invention. The overall aileron apparatuscomprises several elements and functions not common to conventionalaileron apparatus and function. In this example compartments 201 areimplemented in wing 102 b to house one or more rechargeable batteries203, a motor controller 204, and an electric motor 205. This motor inone embodiment is a brushless DC motor which has an advantage of beingcontrollable to start and stop the motor in particular positions, makingit feasible to stop the motor with blades of a two-blade propellerenclosed in a slot in a wing or a flap portion.

Brushless DC motors are not, however, required in embodiments of theinvention, and indeed, in some embodiments motors of other power sourcesmay also be used. A slot 202 of a length and width to accommodate apropeller 206 is implemented through wing 102 b. In this examplepropeller 206 is a propeller having two blades extending in oppositedirections, such that the propeller, stopped in a horizontal aspect, maybe enclosed in slot 202. In FIG. 2 the propeller is shown in a rotaryaspect that blades of the propeller are extending from the slot.Propeller 206 may be in one embodiment a propeller with a single blade,counterbalanced to avoid excessive vibration. The propeller is driven bymotor 205 on a drive shaft passing through a sidewall of slot 202.Propeller 206, spinning, may provide airflow over aileron 207 at anycondition of airspeed of the aircraft, even with the aircraft at astandstill, and therefor provide force to affect attitude of theaircraft. The propeller provides airflow over and under the aileron.

The electric motor, if a brushless DC motor, is controllable to stoppropeller 206 with the propeller horizontal and contained wholly withinslot 202, such that when not being used the propeller offers noresistance to flight of aircraft 101.

As is known in the art, aileron 207 is used for generating a rollingmotion for the aircraft, which may precipitate a banking turn.Typically, when one aileron is moved downward the opposite aileron ismoved upward. For a purpose of the present invention which is to takeoffand land in a bare minimum distance, reducing the velocity of theaircraft to a bare minimum just before touchdown is a requirement. Atsome point in the reduction of velocity, before landing velocity isattained, effect of the ailerons is lost, as the air velocity over theailerons is too slow to provide sufficient cantilever force on the wingto provide control.

In a landing protocol in an embodiment of the present invention a slotcover (not shown in FIG. 2 ) over slot 202 is opened and motorcontroller 204 is commanded to activate motor 205 to drive propeller 206at a time in the landing process that the velocity of the aircraft hasnot yet reduced to the velocity where control by the ailerons is lost.Slot covers are shown and described below with reference to FIG. 4 .Brushless motor 205 driving propeller 206 provides sufficient air volumeand velocity over the aileron so force and torque are adequate tomaintain control all the way to touchdown. For example, in onecircumstance the landing velocity may be 20 knots, while aileron controlmay be lost at forty knots. Use of auxiliary propeller 206 forcing airdirectly over aileron 108 b may provide an apparent airspeed of morethan forty knots over the aileron 108 b while the actual airspeed of theairplane is reduced to 20 knots at landing.

FIG. 2 illustrates apparatus and operation for aileron 108 b, but it isto be understood that a second auxiliary propeller system like thatdescribed with reference to FIG. 2 is also implemented at the outboardend of wing 102 a for aileron 108 a. Both ailerons are enhanced intakeoff and landing with auxiliary propellers and are controlled intandem as is described in enabling detail below.

FIG. 3 is a perspective view of flap system 109 b, shown extended fromwing 102 b of aircraft 101. A flap system in a fixed wing aircraft, ifused, is mirrored on each wing on each side, as it is desired to provideeven lift on both wings to avoid attitude unbalance. A base portion 301interfaces with a main portion 302, which interfaces with an enhancedportion 303, which interfaces with a final portion 304. The portions areshown somewhat more separated than in use for purpose of clearillustration. The portions are connected in the operative system andfollow a track (not shown) as is known in the art to be extended andretracted. The track is curved to produce the curvature of the connectedflap system of main portion 302 and enhanced portion 303 as they extendand retract by a translating system.

The purpose of the extending and retracting flaps is to increase anddecrease the overall lift of the wing. As is well-known in the art, asvelocity of the aircraft decreases in a landing operation, liftdecreases because the velocity of air over the wing also decreases, andat some point, without some means of increasing lift the aircraft willstall. The flaps are the means of increasing lift as velocity drops.Extending the flaps increases wing surface area and curvature, and liftmay be controlled up to a point by flap extension and retraction.

There is a limit to additional lift provided by flap extension inconventional systems. At some point in reducing airspeed, lift fails tosupport the weight of the aircraft, and airspeed may not be reducedfurther without the aircraft falling. This limitation is critical inlanding, as the speed at touchdown together with the mass of theaircraft, cargo and fuel and the efficacy of the braking systemdetermines the length of runway necessary to bring the aircraft to astop. The idea is to land at the lowest airspeed that may be attaineddown to the time of touchdown.

Returning to FIG. 3 , in an embodiment of the invention portion 303 ofthe flap system has a plurality of slots 305, each having a propeller306 driven by an electric motor in a compartment (not shown) in the flapportion also holding a rechargeable battery for driving the propellerwhen needed. These compartments and the elements within are similar tocompartments 201 in FIG. 2 . The motors may be any one of many sorts,but in one embodiment brushless DC electric motors are preferred, asthese are controllable to stop the two-blade propellers withing theslots.

At some point in extending the flaps in an embodiment of the inventionslots 305 are exposed from wing 102 b, and coverings of the slots (notshown) may be opened. When the slots are exposed and opened thepropellers may be engaged. In this example the propellers are adapted inform and direction of rotation to produce increased volume and velocityof air over the flap portions, particularly portions 303 and 304 in thisexample. In embodiments of the invention wherein additional propellersare used in slots to increase lift, the propellers are controlled, whenused, to spin in opposite directions on each wing, to balance torqueproduction on the aircraft by direction of rotation. Overall lift isincreased and may be maintained greater than overall weight of theaircraft to a substantially lower airspeed than in the conventional art.Slot covers are described below with reference to FIG. 4 .

In FIG. 3 it may appear that the propellers in operation may not extendentirely through the flap portion and may not therefore provide airflowunder the flap portion. This is of small consequence, however, becauseit is only airflow and volume over the flap portion that is needed toprovide additional lift. The propellers need not be mounted centrally inthe flap portion but may be positioned more toward the upper region ofthe slot. In operation the propellers will extend above the slot, justas is shown for propeller 206 in FIG. 2 .

FIG. 4A illustrates a flap system 109 b, with a base portion 301, a mainportion 302 which interfaces with an enhanced portion 303 with optionalpropeller covers 401 connected to a final portion 304 in an alternativeembodiment of the invention, wherein batteries, electric motors andpropellers are incorporated into a final extended portion 304 of theflap system of FIG. 3 . In this embodiment there are compartments 403implemented into portion 304 of the flap system, three in this example,and batteries and electric motors are enclosed much as is shown in FIG.2 for the aileron embodiment. The skilled person will understand thatthe assembly and architecture may be different for the embodiment ofFIG. 4A, but the components and functions are essentially the same.

In the embodiment of FIG. 4A the battery and motor compartments areshown closed by cover panels, which may be removable to facilitatemaintenance and service. Shafts from motors in the compartments aredirected outward from the extreme trailing edge of the flap portion, asshown, driving foldable propellers 402, which in one embodiment havethree props, two of which may be seen in FIG. 4A, and one of which ishidden because of the angle of the view. The direction of the shafts isalong a line bisecting the length of the flap portion. Propellers 402thus provide thrust in whatever direction the flap is directed. As shownin FIG. 4A, with the flaps fully extended, portion 304 points primarilydownward, so thrust provided by propellers 402 is primarily upward,depending on the rotational direction of the propellers.

Also, in FIG. 4A slots in flap portion 303, described above in enablingdetail with reference to FIG. 3 , are covered with slot covers 401. Inembodiments of the invention slots for propellers need to be coveredwhen the propellers are not in use because air leakage through the slotsmay affect lift and may produce drag. In various embodiments remotelyoperable covers are provided that may be opened and closed as needed. Inone embodiment a cover may be operable on a track to one side of a slotand may be manipulated by a solenoid operated cylinder, or a hydrauliccylinder. There are a variety of ways that slot covers may be implementsand operated.

Propellers 402 are folding propellers that, in one embodiment extend, asshown in FIG. 4A, by centripetal force when the motor spins. In anotherembodiment there are remotely operable mechanisms in the propeller hubto extend and fold the propellers, and the functionality is controlledby commands in a control system described more fully below. In someembodiments the pitch of the propellers is also remotely controllable.

FIG. 4B illustrates one propeller 402 with props 404 powered by engine405 fully extended. FIG. 4C illustrates one propeller 402 fully folded.In the folded aspect the propellers have very little drag on theaircraft, and with the flaps retracted, the direction of the foldedpropellers is essentially directly to the rear of the wing.

On takeoff, typically the flaps will be fully extended, and propellers402 will provide both forward thrust and lift. The action of propellers402 draws air over the flap sections which also adds to lift. Onlanding, as flaps are retracted, propellers 402 may be reversed forbraking thrust. Given the descriptions above of different embodiments ofthe invention, there may be a substantial plurality of auxiliarypropellers, such as propellers 206, 306, 402, and primary propeller 110.In takeoff and landing procedures any and all of these propellers may beused to provide increased lift or braking as needed by circumstance, andto accomplish these ends, propellers may be reversed in direction,adjustable blades may be used, and speed rpm may be controlled tocontrol thrust as needed.

It will be apparent to the skilled person that apparatus and functionenabled in variations of the invention may or may not all be implementedin specific embodiments. That is, aileron systems supplemented withpropellers for increasing air volume and speed over the ailerons may beused without enhanced flap systems as described. Enhanced flap systemsmay be used without the enhanced aileron systems. Apparatus and functiondescribed in this specification may be used in aircraft of widelydifferent types and may be used in different combinations to satisfydifferent circumstances.

FIG. 5 illustrates a control system in aircraft 101 adapted tofacilitate control of the elements of the system to perform as ahyper-STOL system, capable of takeoff and landing from, for example, arooftop or a landing pad of the size of a tennis court.

Control system 501 in this example has a central processing unit (CPU)502 connected to a local bus 508, which enables the CPU to communicatewith other digital devices in the control system. Bus 508 also comprisesconductors providing power to the digital devices.

CPU 502 may be one of many well-known digital processors in the art ormay be a micro-processor in some embodiments. CPU 502 executes software(SW) 504 in this example and is coupled to a data repository 503 whichmay store one or more code sequences that may be called and executed indifferent circumstances in control, and may also store data values thatare called in control sequences.

Aileron control 505 in FIG. 5 represents remotely operable elements thatare dedicated to functions regarding the left and right aileron systems108 a and 108 b. Among elements involved in aileron control, there aremechanical apparatus that may be commanded by CPU 402 to open and closecovers over slots 202. Once slots 202 are open, motor controllers 204may be commanded by CPU 502 to operate motors 205 to drive propellers206 in either rotary direction. In some embodiments the propellers maybe of a sort that the aspect of the blades may be changed to change thedirection and degree of thrust. In some embodiments the angle of flaps207 may also be controlled under specific circumstances.

Flaps control 506 represents remotely operable elements that arededicated to functions regarding the left and right flap systems 109 aand 109 b. Among elements involved in flap control, there are mechanicalapparatus that may be commanded by CPU 502 to open and close covers overslots 305. Once slots 305 are open, motor controllers 204 may becommanded by CPU 502 to operate motors to drive propellers 306 in eitherrotary direction. In some embodiments the propellers may be of a sortthat the aspect of the blades may be changed to change the direction anddegree of thrust. In some embodiments the extension and retraction ofthe flaps may also be controlled, at least in part, by CPU 502.

Physical sensors 507 represents a group of sensors that report importantreal-time data to CPU 502 for use in control functions. One of the moreimportant data points is airspeed. One or more airspeed sensors areimplemented on a surface of the aircraft to report real-time airspeed.Other sensors determine attitude of the aircraft, including rollattitude and attitude of the fuselage. There may be other sensorsinvolved as well. In processes in embodiments of the present inventionCPU 502 executes one or more code sequences from data repository 503,and commands physical elements for control of the aircraft according todata provided by sensors.

Although control is described here as mostly automated, manual controlof elements in embodiments of the invention is not precluded. Controlmay in some implementations be entirely automatic, in some entirelyautomated, and in others a mixture with some functions automated andsome accomplished manually.

Referring again to FIG. 1 , primary forward propulsion of aircraft 101is provided by engine 105, which may be an internal combustion engine.In some circumstances functions of engine 105 may be controlled, atleast in part, under specific circumstances by CPU 502. Brakes of theaircraft may also, in some circumstances, be controlled, at least inpart, by CPU 502.

FIG. 6 is a flow diagram representing a takeoff process in oneembodiment of the invention. At step 601 the aircraft may be positionedat a beginning end of a takeoff roll, which for purpose of description,may be a relatively small rooftop, or a small flat area, of the sizeperhaps of a tennis court. At step 601 the brakes of the aircraft areengaged.

At step 602 power to primary engine 105 is applied to maximum andpropeller attitude is set, if adjustable to maximum thrust. Also, atstep 602 while the aircraft is still stationary, slots 202 are opened,and propellers 206 are driven to provide additional forward thrust aswell as aileron control. Further, the flaps are extended for maximumlift, slots 305 are opened, and propellers 306 are activated and drivento provide maximum lift for the aircraft as well as additional forwardthrust in addition to that provided by primary engine 105. Propellers402 may also be engaged for additional lift and forward thrust for atakeoff roll. At step 603 the brakes are released, and the aircraftstarts a takeoff roll.

At step 604 liftoff occurs. With the added lift provided by the enhancedflap systems and added thrust provided by all the propellers of theenhanced flap system and the aileron systems the takeoff roll is reducedto a bare minimum. At step 605 altitude and airspeed increase. Theelectric propellers of the enhanced aileron system and the enhanced flapsystem may continue to be used for a time to attain desired altitude andairspeed. At step 606 the electric propellers are stopped slots areclosed and control reverts to conventional manual and computerizedcontrol. At step 607 the aircraft is operated to complete a plannedmission up to a landing process.

FIG. 7 is a flow diagram illustrating a landing process in an embodimentof the invention. At step 701 the aircraft is lined up with a landingarea which may be, as in the case of the takeoff process, a very smallarea. At step 702 the system described with reference to FIG. 5continues to monitor airspeed, attitude, and other aircraft parameters.At step 703, realizing a determined airspeed for the existingconditions, the system extends the flaps for enhanced lift. At step 704propellers 402 are activated. At step 705 slots 305 are opened andpropellers 306 are activated to enhance lift further.

At another point during landing approach, at step 706, airspeedcontinues to decrease. At a second airspeed at which it is determinedthat aileron control will be lost, at step 707 slots 202 are opened andpropellers 206 are activated providing enhanced control for the aileronsbelow an airspeed where control would conventionally be lost. At step708 the aircraft continues to touchdown with both enhanced lift andenhanced control, enabling the airspeed to be reduced to a minimum valueat the point of touchdown. Minimum speed at point o touchdown is animportant aspect of the present invention, because landing roll is afunction of that speed, the mass of the aircraft, and the braking thatmay be applicable.

At step 709 the brake systems of the aircraft are activated, which mayinclude reversing the main propeller, and one or both sets of propellers206 and 306, which may be reversed in rotation or blade pitch to providefurther reverse thrust. At step 710 the aircraft rolls to a stop in aminimum landing roll. The length of the landing roll may be minimized bythe minimum landing airspeed made possible by the increased liftprovided by the enhanced flap system.

In the embodiments described above the example is a fixed wing, singleengine aircraft. In some embodiments elements and functions of theinvention may be applied to aircraft with multiple engines, and otheraircraft. In many embodiments the aircraft may be pilotless, such asmany unmanned aerial vehicles (UAVs).

Innovative Application of Distributed Electrical Propulsion (DEP)

In conventional systems DEP comprises multiple electric motors andpropellers mounted on the leading edge of an aircraft wing. There arecurrently many commercial projects leveraging different configurationsof DEP. Yet DEP has at least two major shortcomings:

1. The E in DEP is for Electric, and electric power is far from ready asa viable propulsion system in any aircraft much larger than a lightsport aircraft or self-launching glider. Energy density of batteries isthe limiting factor and needs to improve by a minimum of three timesbefore electric power becomes viable for aircraft propulsion. Most DEPapplications are 100% battery-powered resulting in short endurance andlimited range. A hybrid power system is required but adds considerablyto complexity and weight leaving marginal useful load and still onlyfractions of the endurance and range of conventional aviation fuelsystems. Furthermore, DEP on most aircraft must always be engaged or theadditional drag of exposed motors and propellers would be significant,even making the aircraft nearly unairworthy.

2. A critical element in aircraft design is clean airflow over flyingsurfaces. Laminar flow is the holy grail for aeronautical engineers.Keeping the airflow attached to the wing as long as possible results inthe highest co-efficient of lift (C/L) and the greatest aeronauticalefficiency.

A principle of DEP is that multiple propellers in front of the wingincrease the airflow over the wing, resulting in increased lift. This istrue, but the airflow is typically so disturbed on both top and bottomsurfaces of the wing that the benefits of greater lift are marginalized.The subject aircrafts' performance increase may be just attributed toadded thrust as it is to any increase in C/L

The present inventors have developed a more efficient and effective useof DEP wherein DEP is employed in an aircraft for only short durationson takeoff and landing and to enhance slow speed roll control. Theinventors term the enhanced system DEP on Demand, or DEPOD. In theunique DEPOD system the motor is installed in the wing interior with thepropeller stowed in a through slot in the wing when not the propeller isnot active, eliminating drag when the propeller is not in use.

In another aspect of the invention a fixed-wing STOL aircraft isprovided with features that provide exceptional slow speed control. FIG.8A illustrates the enhanced-control aircraft in one embodiment, whichhas a fuselage 802, a single engine 803, in this example, driving apropeller 804. Engine 803 in one embodiment consumes auto gas which hasabout 10 times the energy density of battery power, resulting inendurance measured in hours rather than minutes.

Two fixed wings 805 and 806 extend from the fuselage in this embodiment.Each wing has an aileron at an outboard end, one of which, aileron 808,is indicated in detail 8B, which is illustrated in more detail in FIG.8B. Wing 806 has a mirror image aileron also at an outboard end, but theinventor believes that description of aileron 808 sufficiently describesboth. Aileron 808 as in most aircraft is hydraulically activated andbeing raised or lowered induces an upward or downward force on theoutboard end of wing 805, for a purpose of control of aircraft rollabout a long the axis of the fuselage. Control is from input mechanismsin a cockpit of the aircraft, which operate the ailerons such that whenone is raised, the other is lowered by a same amount. In conjunctionwith wing lift the roll of the aircraft by manipulating the aileronscauses the aircraft to turn left or right, depending on the requireddirection of roll.

Returning again to FIG. 8B, in this implementation, three slots 809 a,809 b and 809 c are provided through wing 805, along a front edge ofaileron 808; and dual blade propellers 810 a, 810 b and 810 c aredisposed in the through slots, much in the manner as described above forother embodiments. Propellers 810 a, 810 b and 810 c in this example aredriven by electric motors encased within wing 805; the electric motorsare controlled by input mechanisms in the cockpit.

In one embodiment, the arrangement of the electric motor, propeller andbattery for each aileron may be substantially as shown in FIG. 2 , whichshows one battery bay holding a battery 203, and a propeller 206 in aslot 202 in the wing, the slot and propeller proximate the aileron 207.In other embodiments there may be more than one battery bay and battery,and batteries may be interconnected both in parallel and in series.

In typical use the DEPOD system is needed for less than one minute forboth takeoff and landing, so the battery packs can be exceptionallysmall. The packs are easy to mount and easy to replace.

In one embodiment, the pack is a six-cell LIPO pack with a voltage rangeof 3.0 to 4.2 volts. Each pack has 5500 mAh, and six packs per motor areused. The packs in one embodiment are wired two in series and threeparallel. This arrangement results in an operating voltage range from 36to 50.4 volts. In this example, each pack weighs only 832 g. Six packstotal 5 kg or 10.8 lb. With this low weight, the battery cells may bemounted nearly anywhere. Close to the motor may be preferrable tominimize battery cable weight and voltage drop. The controller andrelated electronics all weigh under half a lb, which is insignificant.

Airflow provided by propellers 810 a, 810 b and 810 c is directed overaileron 808, and imparts upward or downward force depending on theattitude of the aileron and rotational speed of the propellers. Thisforce is entirely independent of velocity of the aircraft, and theinduced force may be applied with the aircraft at a standstill, at a lowforward speed or at a higher forward speed.

Propellers 810 a, 810 b and 810 c each have two blades, and when notpowered are oriented in the slots, to ensure that no portion of thepropeller extends out of the slot. This is desirable so that unwanteddrag is not exerted on the wing of the aircraft when the propellers arenot in use. In one embodiment, the electric motors driving thepropellers are stepper-type motors which may be controlled, to stop atselected positions (steps). In another embodiment, the propellers mayhave magnets at an outboard end of each blade, or elsewhere on theblades, which magnets interact with magnets in the slots, so that when apropeller is not powered, and freewheels, the magnets will interact andthe propeller will be constrained to lie horizontally in the slot. Inone embodiment, the slots may have extendable/retractable covers so thatthe slots may also be closed when the propellers are not in use, furtherreducing drag.

In yet another embodiment of the invention, DEPOD features are alsoincorporated into elements of a tail section indicated as detail 8C,which is illustrated in more detail in FIG. 8C. The skilled person willunderstand that FIGS. 8A, 8B and 8C and accompanying descriptiondescribe specific examples, which may vary considerably in otherembodiments.

FIG. 8C illustrates a tail section of the aircraft of FIG. 8A in thealternative embodiment. The tail section has a vertical stabilizer 811and an operable rudder 812, typically hydraulically activated andcontrolled by input mechanisms in the cockpit. Operation of the rudderin forward flight induces a force to move the tail of the aircraft leftor right, relative to the longitudinal axis of the fuselage.

In this alternative embodiment a vertical slot 815 a is implementedthrough vertical stabilizer 811, and a propeller 816 a is disposed inthe slot, driven by an electric motor, not show, that is housed in thevertical stabilizer, along with one or more battery bays. The batteryarrangements and interconnections may be the same as described for abovefor the bays and batteries associated with the ailerons.

In this embodiment slots 815 b and 815 c are implemented throughhorizontal stabilizer 813, with propellers 816 b and 816 c in the slots,driven by electric motors in the horizontal stabilizer (not shown)powered by batteries in bays, also not shown. Propellers 816 b and 816 cprovide enhanced airflow over elevator 814, which is raised and loweredby mechanisms in the cockpit. In some embodiments there may be separateelevators, one on each side of the horizontal stabilizer. The propellersassociated with the rudder and the elevators provide significantlyenhanced control over the aircraft at low speed.

In the embodiment utilizing DEPOD just at the wing-tip ailerons, the twoelectric motors are used for only short durations for the threepurposes:

1. Takeoff: Takeoff thrust is doubled, which results in a 50-foottakeoff and doubles the climb rate to clear any obstacles and reach1,000-foot cruising altitude.

2. Blown Ailerons: The motors are installed directly in front of theailerons. Increased airflow over the ailerons enables full roll-controlat approach speeds ‘behind the power curve,’ which can be a dangerousspeed due to the ‘aileron reversal’ phenomenon.

3. Reverse Thrust: Electric motors are easily reversable to triplestopping power and remain within a very limited landing space, such as,for example, a helipad. Using DEP for only a few seconds per missionmeans only a few pounds of battery is required.

The engine recharges the batteries fully in cruise, and the aircraft'spayload is not compromised.

The DEPOD design contributes to extreme short takeoff and landingperformance in three ways:

1. Takeoff Thrust: The motors' combined thrust is 140 lb., whichincreases the total thrust of the aircraft by nearly 40%. This resultsin the aircraft attaining takeoff speed significantly quicker, whichshortens takeoff distance considerably and makes climbing over obstaclesmuch shorter and faster.

2. Roll Control: Naturally, aircraft will takeoff and land in shorterdistances if the minimum flying speed is reduced, simple physics.However, besides the stall speed, a limiting factor is low speed controlauthority. Less airflow over the wing is also less airflow over theailerons. Furthermore, the airflow at high angles of attack has greaterseparation from the wing/aileron surface resulting in less roll controlauthority. The physics:

-   -   a. The aircraft must accelerate to greater speeds before        rotating to ensure flight control, particularly in gusty and        turbulent conditions. This means longer takeoff distances, of        course. DEPOD thrust over the ailerons enhances roll control,        mitigating this constraint.    -   b. An aircraft will land shorter if its landing speed is lower.        There is less inertia to dispel. But it is not a safe practice        to approach to land close to the stall speed of an aircraft.        General practice is to approach at 10 to 20 percent above the        stall speed, depending on conditions. And as kinetic energy is a        squared function, this extra speed translates to longer landing        distances. One of the main reasons for this extra speed is to        avoid loss of control which, at low altitudes, may not be        recoverable. One such phenomena is ‘reversed ailerons’ where a        response to an asymmetric gust for example, with aileron input        can increase the angle of attack on one wing above the critical        angle of attack, resulting in a stall/spin. With DEP set at only        20 percent power, the aircraft has roll authority at all        airspeeds. Approach speed is safely reduced, resulting in        shorter landing distance.    -   3. Reverse Thrust: On touchdown the DEPOD motors can be driven        in the opposite direction, providing reverse thrust even before        there is enough weight on the wheels for effective braking.        Reverse thrust is common on airliners but almost never a        consideration in DEP applications. Yet it is not overly        complicated to reverse the direction of an electric motor. It is        much simpler and significantly lighter and cheaper than the        mechanism of a reversing propeller.

FIG. 10 illustrates a control mechanism 1001 similar to a throttlecontroller for a gasoline-fed engine. A frame 1002 guides a lever 1003topped by a ball 1004 for a user's hand grip. The lever is coupled toelectrical control elements such that moving the lever forward from acenter position marked by an arrow on the frame causes the electricmotors to turn in a direction to provide forward thrust for theaircraft, and rpm increases with forward position of the lever. Movingthe lever to the rear from the center position causes the motors to turnin a direction to provide reverse braking thrust, and again the rpm,hence the level of thrust, increases with movement away from the centerposition.

In the embodiment comprising the propellers associated only with theailerons, it is just the propellers in the slots in the fixed wings thatare controlled. In the embodiment also having propellers associated withthe tail section, those propellers are also controlled. In anotherembodiment, separate control mechanisms may be provided for a user tocontrol thrust from different propellers independently.

Significant Considerations:

The DEPOD system is used at full power for only 10-15 seconds ontakeoff. And only at 20% power for up to 30 seconds on approach tolanding, and 5 seconds or less on landing. This totals under one minutetotal running time. The battery packs are so small that they haveminimal impact on payload and aircraft performance.

Batteries may be located in slipper pods with one under each wing nearthe electric motors. FIG. 9 illustrates a short section of wing 805 ofaircraft 801 of FIG. 8A with a slipper pod 818 suspended from the wingby a standoff element 817. This arrangement reduces wing spar load andminimizes the length of heavy gauge battery cables. It also providesquick access for recharging or even a complete battery pod exchange.Furthermore, in the remote event of a battery fire the slipper pods areenabled to be jettisoned and may have a small parachute to reduce anyrisk to objects or people on the ground.

When not engaged, the two-blade propellers on each motor are fixedhorizontally inside the wing so drag is eliminated. A unique magnetsystem secures the propellers horizontally. When the DEPOD is notengaged the aircraft flies normally without any significant loss ofperformance.

In the embodiment also utilizing DEPOD features in the tail section asillustrated in FIG. 8C, all of the advantages of the embodiment usingonly enhanced ailerons are realized, plus added control of the aircraft,plus still more takeoff thrust and reverse thrust on landing.

In yet another aspect of the invention, the innovation of embeddingelectrically driven propellers in the wings of an aircraft is leveragedto provide a further advantage. The fact of wing-tip vortex iswell-known in the art and is caused by high pressure air spilling overthe wing-tip into low pressure space above the wing, creating a vortexfrom each wing-tip that produces drag. Wing-tip vortex has beenaddressed in a number of ways in conventional art. One way is byimplementing an upturned winglet at the wing-tip. In an embodiment ofthe present invention, wing-tip vortex is alleviated or eliminated by anadditional electrically driven propeller.

FIG. 11 is a perspective view of an end of one wing of the STOL aircraftin an embodiment of the instant invention. This view is similar to thatof FIG. 8B and includes the aileron 808 with proximate slots 809 a, band c, with propellers 810 a, b and c, as in FIG. 8B. In the embodimentdepicted in FIG. 11 the tip end of wing 805 is a structure 819 that hasan angled portion 820 that has a drive shaft that turns a propeller 821implemented in a slot 822. In this implementation the slot opens to thewing-tip and propeller 821 is positioned such that it turns through theslot as well as outside the slot, as may be seen in FIG. 11 . Thepropeller turns opposite the direction of the vortex produced by thewing-tip, and effectively alleviates or eliminated the vortex,eliminating thereby the drag that the vortex produces. In one embodimentthe rpm of the propeller may be controlled to increase with an increasein forward speed of the aircraft, therefore the forward speed of thewing-tip.

The skilled person will understand that in this embodiment of theinvention, a mirror image of structure 819 on the end of the wing of theaircraft opposite wing 805 is provided to alleviate or eliminate thevortex produced by the tip of that opposite wing.

The skilled person will understand that the number of slots andpropellers that may be provided in a flap system according to anembodiment of the present invention may vary considerably. The power ofthe brushless electric motors may differ in different embodiments aswell. The nature, design and size of the propellers driven by theelectric motors in the enhanced aileron and flap systems may vary aswell. There are also other electric motors that may be used, rather thanbrushless motors.

Enhanced, Automated DEPOD

It is well known that individual aircraft may be characterized accordingto a “flight envelope” that describes capabilities of a design in termsof airspeed and load factor or atmospheric density. The flight envelopeof an individual aircraft may be different from other aircraft of a samemake and model if the individual aircraft has been modified in some way,like for example using a higher-octane fuel or having a superchargerinstalled. There are many such variations that might be made. This istrue for aircraft that meet the features of STOL aircraft in embodimentsof the present invention, that is, aircraft that incorporate a primarypropulsion system and additionally strategically placed propellers thatare proximate ailerons, flaps or rudders, and may be operated to enhancecontrol of roll, lift or rudder effects. A variety of distributedelectrically driven propellers for such purposes are described in detailabove with reference to drawing figures associated with thisspecification.

In an embodiment of the invention sensors 50 7 as indicated in FIG. 5represent a plurality of sensors that report important real-time data toCPU 502 for use in control functions. One of the more important datapoints is airspeed. One or more airspeed sensors are implemented on asurface of the aircraft to report real-time airspeed. Other sensorsdetermine attitude of the aircraft, including roll attitude and attitudeof the fuselage, such as pitch and yaw. There may be other sensorsinvolved as well. In processes in embodiments of the present inventionCPU 502 executes one or more code sequences from data repository 503,and commands physical elements for control of the aircraft according todata provided by sensors.

CPU 502 may be one of many well-known digital processors in the art ormay be a micro-processor in some embodiments. CPU 502 executes software(SW) 504 in this example and is coupled to a data repository 503 whichmay store one or more code sequences that may be called and executed indifferent circumstances in control and may also store data values thatare called in control sequences. Specific uses of DEPOD are describedabove specifically for exceptionally short takeoff and landing roll.

In an embodiment of the invention utilizing enhanced DEPOD a program isexecuted in background as long as the aircraft is in motion, sensors 507are continuously monitored during program execution, and status iscontinuously compared to preprogrammed values that indicate the aircraftis operating within its specific flight envelope.

FIG. 12 is a diagram illustrating operation of a program and sensors tomaintain an aircraft within its unique flight envelope. In this diagramCPU 1201 may be analogous to CPU 502 of FIG. 5 . CPU 1201 is coupled toa data repository 1202 which may store data regarding a flight envelopefor the specific aircraft in which CPU 1201 is active, and programs thatCPU 1201 may execute, as well as other software and data. CPU 1201 iscoupled to sensors 1204-1211 which report values for a variety of flightcharacteristics of the aircraft in real time. CPU 1201 is also coupledto actuators 1212-1219 and may operate these actuators to change flightcharacteristics of the aircraft. For example, CPU 1201 may controlprimary power to increase or decrease primary thrust. CPU 1201 may alsovary thrust on wing thrusters, and may control flaps, ailerons and therudder of the aircraft. Further, CPU 1201, through program 1203, hasaccess to a preprogrammed set

It should be understood that the flight envelope data does not simplystore a set of constants and variables, but also a set of combinedconditions that define a boundary for safe operation of the aircraft.Within the boundary the aircraft may be said to be operating within theflight envelope. Outside the boundaries remedial action is urgentlyneeded to restore the aircraft to operation within the flight envelope.For example there may be a set of conditions involving altitude,airspeed, and pitch, which indicate a threshold between safe and unsafeoperation. In this set, if any one of the three conditions should fallbelow a threshold constant, the aircraft may be judged outside theflight envelope. And, considering the values for each of the threeconditions in the set, specific action may be indicated. The boundariesof the flight envelope are defined by sets of conditions labeled flightenvelope thresholds 1220.

CPU 102, while the aircraft is in operation, executes a program 1203labeled Enhanced DEPOD program. FIG. 13 is a flow diagram illustratinghow the system works in one embodiment of the invention. At 301 all thesensors are monitored in real time while the aircraft is in operation.At 1302 the system determines whether the aircraft is operating withinor outside the flight envelope. If within (No), control goes back tostep 1301, until step 1302 discovers that the aircraft flightcharacteristics are outside one or more of the stored sets of thresholds1220 (Yes). If Yes, the system drives appropriate actuators at step 103until step 1304 indicates that status has retuned to the flightenvelope.

The system of the invention described herein with reference to FIGS. 12and 13 as applicable to a fixed wing aircraft may be applicable as wellto VTOL aircraft, such as helicopters, and to all sorts of aircraft.

The person of ordinary skill in the art will understand that there maybe many sets of thresholds that will indicate a danger and necessitateimmediate action, and programmed actuation to solve different sets ofdangerous conditions might be numerous.

The skilled person will understand still further that the elementsdescribed in enabling detail in embodiments and implementations abovemay be combined in a variety of ways in different variations of theinvention, all within the scope of the invention. The scope of theinvention is limited only by the scope of the claims.

1. An aircraft having a pilot compartment and a power source,comprising: apparatus adapted to control flight attitude and direction;apparatus adapted to vary power of the power source; sensors sensing atleast altitude, airspeed, power level, and aircraft attitude; a CPUcoupled to a data repository, to the sensors and to actuators adapted tochange the flight attitude and direction and to vary power at the powersource; and safe flight envelope data and conditions stored in the datarepository defining flight conditions at boundaries of safe and unsafeoperation; characterized in that the CPU monitors the sensors while theaircraft is in operation, determines if flight status is outside thesafe flight envelope, and if so, drives appropriate actuators tomanipulate the apparats adapted to control flight attitude and directionand/or the apparatus adapted to vary power of the power source in aprogrammed manner until the flight status is within the safe flightenvelope.
 2. The aircraft of claim 1 wherein the aircraft is VerticalTake Off and Landing (VTOL) aircraft.
 3. The aircraft of claim 1 whereinthe aircraft is a fixed wing aircraft, and the apparatus adapted tocontrol flight attitude and direction comprises ailerons, flaps, and arudder.
 4. The aircraft of claim 3 wherein the aircraft furthercomprises distributed electrically driven, individually controllablepropellers proximate one or more of ailerons, flaps or rudders, themotors powered by one or more on-board batteries.
 5. The aircraft ofclaim 3 wherein the aircraft is a Short Takeoff and Landing (STOL)aircraft having a fuselage with a long axis and a primary engineproviding controllable primary forward thrust to propel the aircraft,further comprising a first aileron implemented proximate an end of afirst fixed wing extending from the fuselage, a second aileronimplemented proximate an end of a second fixed wing, opposite the firstfixed wing, a first slot having a length and a width through the firstfixed wing proximate the first aileron, the slot length substantiallyorthogonal to the axis of the fuselage, a second slot having a lengthand a width through the second fixed wing proximate the second aileron,the slot length substantially orthogonal to the axis of the fuselage, afirst reversible electric motor implemented in the first fixed wingdriving a first two-blade propeller in the first slot, a secondreversible electric motor implemented in the second fixed wing driving asecond two-blade propeller in the second slot, and a control mechanismaccessible to a user in a cockpit of the aircraft, the control mechanismenabling the user to drive the first and second electric motors in asame rotary direction, to reverse the rotary direction, and to drive thefirst and second electric motors at a same rpm in either rotarydirection.
 6. The STOL aircraft of claim 5, further comprising aplurality of slots in linear arrangement along an edge of each aileron,each slot enclosing a two-blade propeller driven by a reversibleelectric motor, wherein all of the propellers are driven in concert. 7.The STOL aircraft of claim 5 further comprising bays implemented in thewings, the bays housing batteries interconnected and coupled to theelectric motors.
 8. The STOL aircraft of claim 6 wherein the two-bladepropeller in each slot is adapted to be constrained wholly within theslot when not being driven by the associated electric motor.
 9. The STOLaircraft of claim 5 further comprising slipper pods slung under thewings, the wings and the slipper pods housing batteries interconnectedand coupled to the electric motors.
 10. The STOL aircraft of claim 9wherein the slipper pods are adapted to be jettisoned on command.
 11. Amethod to maintain operation of an aircraft having a pilot compartmentand a power source within a safe flight envelope, comprising: monitoringsensors sensing at least altitude, airspeed, power level, and aircraftattitude by a CPU coupled to a data repository, to the sensors and toactuators adapted to control apparatus adapted to control flightattitude and direction to change the flight attitude and direction andto vary power at the power source; determining whether flight status isoutside a safe flight envelope by comparison of real time sensed valuesto stored safe flight envelope data and conditions in the datarepository defining flight conditions at boundaries of safe and unsafeoperation; if so, driving appropriate actuators to manipulate theapparats adapted to control flight attitude and direction and/or theapparatus adapted to vary power of the power source in a programmedmanner until the flight status is within the safe flight envelope. 12.Performing the method of claim 11 with a Vertical Take Off and Landing(VTOL) aircraft.
 13. Performing the method of claim 11 with a fixed wingaircraft having ailerons, flaps, and a rudder.
 14. Performing the methodof claim 13 with an aircraft further comprising distributed electricallydriven, individually controllable propellers proximate one or more ofailerons, flaps or rudders, the motors powered by one or more on-boardbatteries.
 15. Performing the method of claim 13 with a Short Takeoffand Landing (STOL) aircraft having a fuselage with a long axis and aprimary engine providing controllable primary forward thrust to propelthe aircraft, further comprising a first aileron implemented proximatean end of a first fixed wing extending from the fuselage, a secondaileron implemented proximate an end of a second fixed wing, oppositethe first fixed wing, a first slot having a length and a width throughthe first fixed wing proximate the first aileron, the slot lengthsubstantially orthogonal to the axis of the fuselage, a second slothaving a length and a width through the second fixed wing proximate thesecond aileron, the slot length substantially orthogonal to the axis ofthe fuselage, a first reversible electric motor implemented in the firstfixed wing driving a first two-blade propeller in the first slot, asecond reversible electric motor implemented in the second fixed wingdriving a second two-blade propeller in the second slot, and a controlmechanism accessible to a user in a cockpit of the aircraft, the controlmechanism enabling the user to drive the first and second electricmotors in a same rotary direction, to reverse the rotary direction, andto drive the first and second electric motors at a same rpm in eitherrotary direction.
 16. Performing the method of claim 15 with the STOLaircraft further comprising a plurality of slots in linear arrangementalong an edge of each aileron, each slot enclosing a two-blade propellerdriven by a reversible electric motor, wherein all of the propellers aredriven in concert.
 17. Performing the method of claim 13 with the STOLaircraft further comprising bays implemented in the wings, the bayshousing batteries interconnected and coupled to the electric motors. 18.Performing the method of claim 17 wherein the two-blade propeller ineach slot is adapted to be constrained wholly within the slot when notbeing driven by the associated electric motor.
 19. Performing the methodof claim 15 with the STOL aircraft further comprising slipper pods slungunder the wings, the wings and the slipper pods housing batteriesinterconnected and coupled to the electric motors.
 20. Performing themethod of claim 19 wherein the slipper pods are adapted to be jettisonedon command.